Statistical Analysis of Impedance Data for Jet Turbine Oil Additives

A gold, parallel-plate capacitor test cell was used to make electrochemical impedance spectroscopy (EIS) measurements on high resistivity gas turbine engine oil as a function of the oil additive type.The additive effects on the EIS response were determined by analyzing ester-based basestock oil mixed with a single additive.This work was performed for four different additives:antioxidant, metal deactivator, anti-wear, and extreme pressure.Multiple measurements were made for each basestock-single additive mixture.To determine whether the EIS response of each additive showed a significant difference, statistical analysis was performed on the data using a student’s t-test.Low-frequency data showed the largest difference in additive responses.Statistical analysis showed that the extreme pressure additive has the greatest effect on oil impedance.Mixtures of antioxidant and metal deactivator additives did not show interaction.